QuadraTherm introduces a patented four-sensor thermal mass air flow meter design—three precision platinum temperature sensors and one patented DrySense mass velocity sensor backed by a lifetime warranty. Suitable for compressed air applications, This precision instrument is available in the 640i air/gas flow meter insertion version and this 780i inline version.

Accuracy Never Before Possible

From Sierra’s beginning over 40 years ago, Founder Dr. John G. Olin was driven by the vision of supplying industrial customers with the world’s most accurate thermal air mass flow meter. He knew it was a “sensor” game. The development of an industrialized metal-sheathed sensor in the early ’80s was Sierra’s first big step, but Dr. Olin, a driven innovator who saw thermal mass flow as his life’s work, knew this was only the beginning. Many successful innovations followed, but in 1999 Sierra experienced a major breakthrough with the introduction of its patented, no-drift DrySense™ thermal mass velocity sensor. Sierra engineers now recognized they were on the cusp of realizing Dr. Olin’s vision.

Realizing the Vision

Thermal technology, by its very nature, uses the physics of heat transfer and conservation of energy in a closed system to measure mass flow rate. This means that for thermal air mass flow meters to achieve greatest accuracy, they must solve the First Law of Thermodynamics (Heat Energy In = Heat Energy Out) for each data point. As you can imagine, solving the First Law in a flow instrument was no easy task. By Dr. Olin’s own accounting, it took decades of his and the Sierra engineering team’s “hard-nosed dedication to excellence,” years of testing and his stack of yellow note pads over five feet high—j jammed with his handwritten equations and designs—to finally yield the secret in the form of QuadraTherm and Raptor OS, now both patented worldwide.